trigger StudentTestTrigger on Student__c (before update, before insert) {
    
    // 测试审批流是否能触发Trigger，结论：可以触发
    if(Trigger.isUpdate) {
        for(String id : Trigger.newMap.keySet()) {
            String oldStatusVal = Trigger.oldMap.get(id).approvalStatus__c;
            String newStatusVal = Trigger.newMap.get(id).approvalStatus__c;
            if(oldStatusVal != newStatusVal && newStatusVal == '审批通过') {
                Double oldSchoolFee = Trigger.newMap.get(id).School_Fee__c;
                Trigger.newMap.get(id).School_Fee__c = oldSchoolFee + 1;
            }
        }
    }
}